This kind of collision can be called the Circle to Circle Collision, where the distance of both circle's centers are equal or less than the sum of both radii.

the distance formula is the equation to use
D = Math.sqrt( Math.pow(x1 - x2) + Math.pow(y1 - y2) );
this is actually not a great way to do this equation
so you just make it so you don't use Math objects